Tunnel boring machines (TBMs) are large machines that excavate below the ground surface, while simultaneously installing concrete lining units to build a tunnel.

The Forrestfield-Airport Link’s two tunnels will be constructed with 54,000 concrete segments. A Forrestfield warehouse has been transformed into a facility to batch the concrete and create segments to line the two tunnels.

Emergency egress shafts provide safe exit points in the event of an emergency, and access to the Forrestfield Line's twin-bored tunnels for maintenance,

Dewatering involves temporarily lowering the water table to allow soil to be excavated from a work site without it refilling with water. This process will be used in construction of the project's underground station boxes and portals.